^
It's a hit or miss. It will even worse the last week of June but you will encounter schoolgroups already in that week aswell. I once ended up (10 years ago or so) with 30000 schoolkids in WB. I can tell you, it was terrible But you might be lucky and only face light crowds aswell of course. 2 years ago I was on the same day in Duinrel with no crowds and in Drievliet with heavy crowds. So really, it is a hit or miss but be prepared.